This application addresses broad Challenge Area (15) Translational Science and specific Challenge Topic, 15-OD(ORDR)-101: Pilot projects for prevention, early detection and treatment of rare diseases. Specifically, this application is focused on developing gene therapy as a treatment for the rare disease Primary Ciliary Dyskinesia (PCD). PCD is predominantly inherited as an autosomal recessive disease caused by mutations in genes that are required for the normal function of the motile cilia that line the respiratory tract. In the airways, disruption of normal ciliary activity results in an absence of mucociliary clearance and leads to an increased incidence of respiratory infections. Currently, there is no specific treatment for PCD, and affected individuals suffer from a life-long pattern of recurring respiratory infections, ultimately leading to bronchiectasis. Recently, mutations that cause a significant fraction of PCD have been identified in a small number of ciliary proteins, including dynein intermediate chain 1. The identification of the specific genes that are mutated in cases of PCD provides the opportunity to use gene transfer techniques to correct the genetic defect and restore normal ciliary function and pulmonary health to these patients. To test the overall hypothesis that gene therapy can be an effective treatment for PCD, this work will use a newly developed mouse model of PCD. This mouse model has a mutation in the dynein intermediate chain 1 gene and exhibits many of the features of the human disease, including structural defects of respiratory cilia, impaired ciliary activity, a complete lack of mucociliary clearance, and the spontaneous development of respiratory disease. A newly developed gene transfer vector that is based on the equine infectious anemia virus and is pseudotyped with fowl plaque influenza virus hemagglutinin protein will be used to express the normal dynein intermediate chain 1 protein in the mouse model of PCD. The ability of the gene transfer vector to correct ciliary activity and mucociliary clearance will be measured both in vitro and in vivo. In addition, the same viral vector will be tested for its ability to correct ciliary activity and mucociliary function in human PCD cells in vitro. These studies will advance the development of gene therapy as a treatment for PCD and other diseases. The specific aims of this proposal are: 1. To test the hypothesis that an HA-pseudotyped lentiviral vector expressing the normal Dnaic1 cDNA can restore ciliary activity to tracheal airway epithelial cells from PCD mice in vitro. 2. To test the hypothesis that an HA-pseudotyped lentiviral vector expressing the normal Dnaic1 cDNA can provide stable, long-term correction of ciliary activity and mucociliary clearance and prevent disease in PCD mice in vivo. 3. To test the hypothesis that HA-pseudotyped lentiviral vectors can restore ciliary activity and mucociliary transport to human PCD cells. PUBLIC HEALTH RELEVANCE: This project will test a new therapy for people who have diseases caused by mutations in genes that are important for the proper function of the cells that line their airways and suffer from frequent lung infections. A new gene therapy vector will be tested to determine if it can transfer a normal copy of the mutated gene into the affected cells and correct their function. The information gained from these studies will advance the field of gene therapy and may be useful to the treatment of many genetic diseases.